By: 13 January 2020
Showcase of abstracts at Orthopaedic Knee Conference

This year, the speakers judged the abstracts presented on the podium at the Royal Armouries in Leeds. We take a look at the top three recognised as outstanding by the panel

1st place

Rehab your own knee: Improving the outcome of knee injuries using a timely, low-cost home exercise programme

Author: Nick Evans, Scarborough Hospital, York Teaching Hospitals NHS Trust

Background: Historically, acute knee injuries have been treated with immobilization, bracing, and physiotherapy, but scientific literature is sparse. With a wait-time of more than four-weeks for physiotherapy at the study hospital, we had concerns about knee stiffness and weakness.

Methods: Prospectively, all new-patient A&E referrals attending an Acute Knee Injury Clinic were treated using a simple four-step home exercise programme (HEP) designed by the author. Technical demonstration of the exercises, emphasising the benefits was aimed at optimising patient participation. Data was recorded at time zero and after four-weeks of HEP.

Results: 40 consecutive patients (65 per cent male) were studied over a three-month period, with a median age of 28 years (range nine–62) and median BMI of 26kg/m2 (range 20 – 35). Injuries sustained involved: cruciate-ligament (35 per cent); collateral-ligament (17.5 per cent); patello-femoral joint (17.5 per cent); meniscus (12.5 per cent); bruise/graze (10 per cent) and fracture (7.5 per cent). 80 per cent had a traumatic knee joint effusion, unable to bear weight through the injured leg. At time zero, the average range of knee motion (ROM) was 75.5 degrees. After four-weeks in the Rx Group (n=28) the average ROM was 128.5 degrees. The average increase ROM was 60 +/- 20 degrees, which constitutes an 85 per cent (60/70) increase in ROM using the HEP for four weeks. All patients (100 per cent) were able to walk unaided and achieve full knee extension, and did not require physiotherapy. In a control group (n=12) receiving historic treatment (knee immobilisation plus physiotherapy, without HEP) the average ROM after four-weeks was unchanged at 76 degrees.

Conclusion: Functional improvements are identified in all Rx Group patients within a short four-week time period. In the treatment of Acute Knee Injuries, the HEP is: immediate, effective, patient-centred, and low-cost (physiotherapy is not required saving £50 per patient per session).

Disclosure: Nothing to disclose

2nd place

Comparison of surgical site infection risk between warfarin, aspirin and low molecular weight heparin when used for venous thromboprophylaxis following knee or hip arthroplasty – a systematic review and meta-analysis of nine studies, including 184,105  cases

Authors: Hughes L, Lum J, Anand A, Blackpool Teaching Hospitals NHS Trust; Mahfood ZR, Malik RA, Weill Cornell Medicine, Qatar; Charalambous CP, School of Medicine, University of Central Lancashire and Blackpool Teaching Hospitals NHS Trust

Aim: To compare the surgical site infection risk between warfarin, low molecular weight heparin (LMWH) and aspirin when used for venous thromboembolism (VTE) prophylaxis following total knee or hip arthroplasty. 

Methods: A systematic literature search was conducted on 27 November 2018, using PubMed, CINAHL and Cochrane Register of Controlled Trials (CENTRAL) databases to identify studies that compared warfarin, LMWH and/or aspirin in relation to surgical site infection rates following hip or knee arthroplasty. Meta-analyses were performed to compare the infection and VTE risk between groups.

Results: Nine articles including 184,105 patients met the inclusion criteria. Meta-analysis showed that warfarin prophylaxis is associated with a higher risk of deep/reoperation (OR 1.929, 95 per cent CI 1.197-3.109, P=0.007) and overall (OR 1.610, 95 per cent CI 1.028–2.522, P=0.038) surgical site infection as compared to aspirin in primary total joint arthroplasty, with similar findings also seen with primary and revision procedures combined. There was no significant difference in infection risk between warfarin and LMWH and between LMWH and aspirin. There was a non-significant trend for VTE risk to be higher in warfarin compared to aspirin therapy for primary procedures (OR 1.6, 95 per cent CI 0.875-2.926, P=0.127) and this was statistically significant when both primary and revision cases were included (OR=2.674, 95 per cent CI 1.143-6.255, P=0.023).

Conclusions: These findings caution the use of warfarin for VTE prophylaxis for hip and knee arthroplasty. Further randomised head-to-head trials and mechanistic studies are warranted to determine how new age anticoagulants impact infection risk.

3rd place

Association between patellofemoral anatomy and chondral lesions of the knee in patellofemoral instability

Authors: O O’Malley, A Choudhury, A Biggs, V Ejindu, CB Hing, Department of Trauma and Orthopaedics, St George’s University Hospitals NHS Foundation Trust; AJ Humdani, St George’s University London; and TO Smith, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford

Purpose: Chondral injury is a serious consequence of patellar dislocation and patellofemoral instability (PFI). There is limited data on the relationship between radiological features such as sulcus angle and patellar height to the presence, location and severity of chondral lesions. The purpose of this study was to answer this question.

Methods: A cohort of 101 patients undergoing isolated arthroscopy or arthroscopy at the time of corrective re-alignment surgery were identified. The prevalence of chondral, ligamentous and meniscal injury was determined and correlated to the sulcus angle, tibial tubercle trochlear groove distance and patellar height on MRI scans.

Results: In total, data were available for analysis for 101 patients. At arthroscopy, the patella demonstrated the highest incidence of chondral injury (68 per cent) followed by the trochlear groove (40 per cent). Lateral meniscal injuries were noted in 6 per cent of patients, medial meniscal injuries in 2 per cent and injury to the ACL in
3 per cent. There was a significant correlation between severity of chondral injuries and tilt angle (p=0.05). The occurrence of injury to the lateral and medial femoral condyle was significantly associated with the Insall Salvati (IS) ratio(p=0.004). Medial meniscal tear was associated with tilt angle (p=0.05). 

Conclusion: PFI is associated with chondral injury. The tilt angle of the patella is associated with the severity of patellar chondral injuries and incidence of medial meniscal tear. The IS ratio was associated with injury at the femoral condyles. Given these associations, patellar height and tilt angle may be used to risk stratify patients in order to consider early surgical intervention to avoid further chondral injury.